MTH Flashcards
Explain how an arteriole can reduce blood flow into capillaries.
- muscle contracts
- narrows arteriole
Describe how the heart maintains a one-way flow from left atrium to aorta.
- atrium has highER pressure than ventricle
- atrioventricular opens
- ventricle has highER pressure than atrium
- atrioventricular close
- ventricle has highER pressure than aorta
- semilunar opens
- highER pressure in aorta than ventricle
- semilunar close
- contraction causes increase in pressure
How does diaphragm movement lead to air in lungs.
- contracts and flattens
- lung volume increase
- pressure inside lungs lower than atmospheric pressure
- air moves in
How are lungs adapted to allow oxygen exchange.
- many alveoli so large surface area
- many capillaries so large surface area = fastER diffusion
- thin epithelium = shortER diffusion distance
- ventilation/circulation so maintain conc gradient = fastER diffusion
How we breathe in and out.
- trachea, bronchi, bronchioles, alveoli
- breathe IN = Diaphragm contracts, external intercostal muscles contract
- volume increases and pressure decreases in thoracic activity
- breathe OUT = diaphragm relaxes, internal intercostal muscles relax
- volume decrease and pressure increase in thoracic activity
Pathway taken by oxygen molecule.
- alveolar epithelium
- endothelium of capillary
Why does death of alveolar epithelium cells reduce gas exchange?
- reduced surface area
- increased distance for diffusion
- reduced rate of gas exchange
How walls of arteries and arterioles relate to functions.
- elastic tissue stretches under pressure
- recoils
- evens out pressure
- muscle contracts
- diameter of lumen reduced
- changes flow
- epithelium smooth
-reduces friction
Why does wall thickness of aorta change during cycle.
- wall stretches
- pressure increases
- wall recoils
- ventricle relaxes
- maintains smooth flow
How to improve quality of scientific drawing.
- single lines/no sketching
- add labels
- add magnification scale
- draw all parts to same scale
- no shading
Two precautions when clearing away after dissection.
- carry scalpel around facing down
- disinfect hands with soap
- disinfect surfaces
- put paper towels in a separate bin to dispose
How is tissue fluid formed and returned.
Formed=
- high blood pressure
- forces water out
- large proteins remain in capillary
Return =
- low water potential in capillary
- due to proteins
- water enters capillary
- by osmosis
SA:V in mammals.
- smallER = greater SA:V
- as more heat loss
- greater rate of respiration
- oxygen required for respiration
Coronary heart disease.
